1. Field of the Invention
The present invention relates to: a camera system comprising a lens assembly that is loaded with an image taking optical system for forming a subject light image, and a camera body on which the lens assembly is detachably mounted, the camera body applying a predetermined image processing to image data; the camera body constituting the camera system; and the lens assembly constituting the camera system.
2. Description of the Related Art
Hitherto, there is known an interchangeable lens digital camera in which an interchangeable image lens unit incorporating therein an image taking lens is mounted on a camera body incorporating an imaging device. According to the interchangeable lens digital camera, a subject light image formed by an image taking lens is fed to the imaging device provided on the camera body to create photographic image data. Accordingly, it is possible to reuse an interchangeable lens, which is used in a film type of single-lens reflex camera for recording a photographic image on a silver halide film.
However, for example, in the event that a large scale of image taking lens, which is excellent in an optical property, is mounted on a camera main body that incorporates therein a small type of imaging device that is low in resolution, while the image taking lens forms the subject light image with great accuracy, the imaging device cannot read the subject light image with great accuracy. This involves such a problem that it is difficult to make the best use of a property of the image taking lens. In order to solve the problem, there is developed an interchangeable head digital camera wherein a lens unit having an imaging device, which incorporates therein an image taking lens and an imaging device, that is, a camera head (hereinafter, the lens unit having the imaging device will be referred to as the camera head), is mounted on a camera body (cf. for example, Japanese Patent Application Laid Open Gazette TokuKai Hei. 8-172561 and Japanese Patent Application Laid Open Gazette TokuKai 2000-175089) According to the interchangeable head digital camera as mentioned above, a provision of CCD suitable for a size of the image taking lens and an optical property in the camera head beforehand makes it possible to obtain a high picture quality of photographic image through performing photography making the best use of the image taking lens. However, it is impossible for the interchangeable head digital camera to use an interchangeable lens for a film type of single lens reflex camera, different from an interchangeable lens digital camera.
By the way, according to the interchangeable lens digital camera and the interchangeable head digital camera as mentioned above, the lens unit and the camera body are provided with the associated CPUs, respectively. It is general that the lens unit CPU performs controls for lens drive processing to be carried out in the lens unit, and the camera body CPU performs obtaining of various sorts of information entered by a user in accordance with menu screens and the like, and image processing for photographic image.
Of the various types of processing to be carried out in the lens unit, there is one that needs a user's instruction as to parameters. The lens unit and the camera body each save a list that associates beforehand processing to be executed in the lens unit with various sorts of information necessary for displays of an input screen for inputting by a user parameters necessary for execution of the processing, or an input screen for inputting a sort of the parameters. For example, in the event that an adjustment of ISO speed is performed in the lens unit, first, the lens unit CPU informs the camera body CPU of execution of ISO speed adjustment processing. The camera body CPU obtains information of an input screen associated with the ISO speed adjustment processing of the previously saved list, and transmits data for an input screen, which is previously stored in the memory, to the display screen, so that the input screen is displayed. When the user inputs a parameter in accordance with the input screen displayed on the display screen, the camera body CPU transmits the entered parameter to the lens unit CPU, so that the lens unit CPU performs an adjustment of the ISO speed in accordance with the received parameter. In the manner as mentioned above, between the lens unit and the camera body, processing to be executed in the lens unit is associated beforehand with a sort of the parameter necessary for the execution of the processing. This feature makes it possible for the lens unit to execute processing according to the user's instruction.
However, according to the method as mentioned above, for example, in the event that the lens unit, which is loaded with a new function, is connected to the camera body, it is impossible for the camera body CPU to display an input screen for receiving an input a parameter necessary for an implementation of the new function, since the new function is not listed. Thus, even if the lens unit is loaded with various functions, when the functions are not listed, the user cannot use the functions.